Valeraldehyde and process for its preparation

ABSTRACT

Bidentate phosphine ligands of the formula  
                 
 
     wherein the substituents are as defined in the specification and a process for preparing linear aldehydes by hydroformylating internal olefins using such phosphine ligands.

SUMMARY OF THE INVENTION

[0001] Novel bidentate phosphine ligands and a process for preparinglinear aldehydes by hydroformylating internal olefins using saidphosphine ligands.

STATE OF THE ART

[0002] Linear aldehydes, particularly butyraldehyde, are of greatindustrial importance and, after further processing to the alcohols, arewidely used in the plasticizer, solvent and polymer sector. Sincemixtures of internal olefins, such as raffinate II, are produced inlarge amounts as a by-product in refining and cracking in theoil-processing industry, hydroformylating internal olefins to producelinear aldehydes is of great industrial interest.

[0003] The term “internal olefins” means those olefins which have atleast one non-terminal double bond. However, this does not mean thatinternal olefins may not have a terminal double bond. Therefore, theterm “internal olefin” is also taken to mean, for example, a compoundsuch as 1,3-pentadiene.

[0004] It is known to prepare aldehydes by hydroformylating olefinsusing a catalyst with linear and branched aldehydes generally beingformed simultaneously:

[0005] For a reaction of this type, bidentate ligands are also used as acatalyst component. In this case, for example, the ligand can be usedtogether with a metal or in the form of a complex with a metal.

[0006] The term “bidentate ligand” means here and hereinafter moleculesof the formula

R=P-E-P=R

[0007] wherein, -P=R and R=P- are individually organic cyclic groups inwhich the phosphorous atoms are part of the cyclic system and are linkedto the cyclic system via a phosphorus-carbon bond or a phosphorus-oxygenbond; and E is a bridging group which links the corresponding phosphorusatoms of the two organic cyclic groups.

[0008] For industrial hydroformylation reactions, a high selectivity forthe linear or branched aldehydes is particularly necessary. Thisselectivity is generally expressed by what is termed the 1/bratio=(linear aldehyde)·(branched aldehyde)⁻¹. The hydroformylation isdescribed by Frohning and Kohlpaintner in Applied Homogeneous Catalysiswith Organometallic Compounds, Ed. B. Cornils, W.A. Hermann; VCH,Weinheim 1966, Vol. 1, pp. 29-104. Another example of the use ofbidentate ligands in catalytic reactions is the hydrogenation describedby Brunner in Applied Homogeneous Catalysis with OrganometallicCompounds, Ed. B. Cornils, W.A. Hermann; VCH, Weinheim 1966, Vol. 1, pp.201-219.

[0009] EP-0 530 015 A1 describes the use of ligands of the typeR=P-E-P=R, such as the ligand of the formula

[0010] which are used in metal catalysts for the chiral synthesis ofpharmaceuticals and novel intermediates. JP 07082281 A2 (JP 93-225998)discloses that ligands of this structural type can be used inhydroformylation for the synthesis of branched olefins with highselectivity.

[0011] Hopps describes in J. Organ. Chem., 1981, Vol 46, pp. 4422- 4427,the use of a ligand of the type R=P-E-P=R, such as the ligand of theformula

[0012] for the asymmetric hydroformylation of vinyl acetate, vinylpropionate and vinyl benzoate, the selectivity for the branchedaldehydes being 75-95%.

[0013] EP-0 213 639 B1 describes a bidentate phosphite ligand of thetype R=P-E-P=R, where P=R or R=P are individually organic cyclic groupsin which the phosphorus atoms are part of the cyclic system and arelinked to the cyclic system via a phosphorus-oxygen bond, and E is abridging group which links the two phosphorus atoms of the two organiccyclic groups and where the phosphorus atom is linked to the bridginggroup E via a phosphorus-oxygen bond. These ligands are, for example, aligand of the formula

[0014] and can be used for hydroformylating internal olefins to producelinear aldehydes. The multistage synthesis of this ligand and the lowerstability of phosphite ligands compared with phosphine ligands ingeneral is, however, a disadvantage for industrial implementation.

OBJECTS OF THE INVENTION

[0015] It is an object of the invention to provide novel ligands and aprocess for hydroformylating internal olefins to produce linearaldehydes, which overcomes the disadvantages of the processes describedfor hydroformylating internal olefins and which converts internalolefins to produce linear aldehydes with high selectivity.

[0016] These and other objects of the invention will become obvious fromthe following detailed description.

THE INVENTION

[0017] The novel ligands of the invention are bidentate phosphineligands of the formula

[0018] wherein R1, R2, R3 and R4 are independently selected from thegroup consisting of hydrogen, fluorine, alkyl of 1 to 8 carbon atoms,alkoxy of 1 to 8 carbon atoms, acyloxy of an organic carboxylic acid of1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, aryloxy of 6 to 18carbon atoms, —CN, —CF₃, —CHO, —SO₃H, —SO₃M, —SO2R, —SOR, —NH₂,—NH—alkyl of 1 to 8 carbon atoms, —N—alkyl₂ of 1 to 8 carbon atoms,—NHCO—alkyl, —N—(alkyl)—(CO—(alkyl) where the alkyl have 1 to 4 carbonatoms, —COO—alkyl of 1 to 8 carbon atoms, —CONH₂, —CO—alkyl of 1 to 8carbon atoms, —NHCOH, —NHCOO—alkyl of 1 to 4 carbon atoms, —Co—aryl of1to 8 carbon atoms, —COO—aryl of 1 to 8 carbon atoms, —CHCH—CO₂—alkyl of1 to 8 carbon atoms, —PO—(—aryl)₂ of 1 to 8 carbon atoms, —PO—(alkyl₂)of 1 to 4 carbon atoms; M is a cation selected from the group consistingof alkali metal ions, alkaline earth metal ions, —NR₂H₂, —NR₃H, —NRH₃,—NR₄, —NH₄, —PR₂H₂, —PR₃H, —PRH₃, —PR₄ and —PH₄; or R1, R2, R3 and R4,with one another, together form at least one aliphatic or aromatic ringof 5 to 20 carbon atoms; E is a bridge linking the two phosphorus atoms,where the number of atoms situated between the two phosphorus atoms is 2and 6, selected from the group consisting of C, N, Si, S, O, P, Fe andAs; X is selected from the group consisting of —O—, —S—, —Si(R^(a))₂—,—Si(OR^(a))₂—, —N(C(O)R)—, —N(R^(b)), —C(R^(c)) (R^(C)) —, —C (O)—,—N(SiR^(d))—, —P(R^(d))—, —P(O)(R^(d))—, —C=C(R^(c))(R^(c))—and—P(OR^(d))— wherein

[0019] R^(a) is alkyl of 1 to 8 carbon atoms,

[0020] R^(b) is aryl of 6 to 18 carbon atoms,

[0021] R^(c) is selected from the group consisting of hydrogen, alkyl of1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, alkoxy of 1 to 8carbon atoms, aryloxy of 6 to 18 carbon atoms, R^(a)(O)— and R^(b)(O);and

[0022] R^(d) is one of R^(a) or R^(b).

[0023] According to a preferred embodiment, E is one of the followinggroups:

[0024] wherein X is selected from the group consisting of —O—, —S—,—Si(R^(a))₂—, —Si(OR^(a))₂—, —N(C(O)R^(a))—, —N(R^(b))—, —C(RC) (R)—,—C(O)—, —N(SiRd)—, —P(R^(d))—, —P(O) (R^(d))—, —C=C(R^(c)) (R^(c))— and—P(OR^(d))—,

[0025] R^(a) is alkyl of 1 to 8 carbon atoms

[0026] R^(b) is aryl of 6 to 18 carbon atoms

[0027] R^(C) is selected from the group consisting of hydrogen, alkyl of1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, alkoxy of 1 to 8carbon atoms, aryloxy of 6 to 18 carbon atoms, R^(a)(O)— or R^(b)(O)—;and R^(d) is one of R^(a) or R^(b);

[0028] Y is oxygen or sulfur; and

[0029] R5s are individually aryl of 6 to 18 carbon atoms or alkyl of 1to 8 carbon atoms.

[0030] In accordance with a further preferred embodiment of theinvention, E is one of the following groups:

[0031] where R6 is alkyl of 1 to 8 carbon atoms or aryl of 6 to 18carbon atoms; Z is oxygen or nitrogen, and n is an integer of 2 to 6.

[0032] The phosphine ligands of the invention are used, in particular,in a process for preparing linear aldehydes by hydroformylating internalolefins of 4 to 12 carbon atoms in the presence of a bidentate phosphineligand of the formula

[0033] wherein R1, R2, R3, R4, M, E and X are defined as above.

[0034] According to a preferred embodiment of the process of theinvention, E is one of the following groups:

[0035] wherein X, Y, R5 and R6 are defined as above.

[0036] In accordance with a further preferred embodiment of the process,E is one of the following groups:

[0037] where R⁶ is an alkyl of 1 to 8 carbon atoms or aryl of 6 to 18carbon atoms; Z is oxygen or nitrogen; and n is an integer of 2 to 6.

[0038] It has proved to be particularly expedient if the reaction iscarried out in the presence of rhodium at a concentration of from 1 to1000 ppm, preferably from 10 to 250 ppm, based on the total reactionmixture. The ratio of rhodium to ligand can, in this case, be between1:1, and 1:100, preferably between 1:1 and 1:20.

[0039] The temperature during the reaction is generally between 10 and180° C., preferably between 80 and 140° C., and the pressure is between0.1 and 200 bar, preferably between 1 and 100 bar.

[0040] The reaction can be carried out in the presence of a solventwhich may be selected from the group consisting of ether, C0₂,fluorinated hydrocarbons, toluene and benzene. However, the solvent canalso be a polar aprotic solvent which is preferably selected from thegroup consisting of DMAC, DMF or NMP.

[0041] It is also possible to carry out the reaction in the presence ofan oligomeric linear aldehyde, preferably particular in the presence ofthe trimer of the linear aldehyde to be prepared, which here also actsas solvent. Also, it has proved to be expedient to carry out thereaction in a two-phase mixture of the solvent and water.

[0042] The CO/H₂ ratio during the hydroformylation of the invention isusually between 1:10 and 10:1, preferably between 1:2 and 2:1.

[0043] In the following examples, there are described preferredembodiments to illustrate the invention. However, it should beunderstood that the invention is not intended to be limited to thespecific embodiments.

EXAMPLES

[0044] General Synthesis Method:

[0045] All experiments are carried out using standard Schlenk techniguesunder an argon atmosphere. The chemical were obtained from Acros Chimicaand Aldrich Chemical Company. Rh(CO)₂(dipivaloyl methanoate) wasprepared by the processes described in the literature (H. T. Teunissen,F. Bickelhaupt “Phosphor, Sulfur” 1996 118, pp. 309-312; H. K. A. C.Coolen, P. W. N. M. van Leeuwen, R. J. M. Nolte “J. Org. Chem.” 1966,61, pp. 4739-4747). The NMR measurements were carried out using a BrukerAMX 300 spectrometer.

[0046] Preparation of the Diphosphine Ligands 2 a-2 c:

[0047] 3.7 ml of a solution of N-butyllithium in hexane (2.5 mol, 9.3mmol) were added to a mixture of 2.00 g of 4,5-dibromo-2,7-di-t-butyl-9, 9-dimethylxanthene (compound 3) (4.16 mmol) in 50 ml ofTHF at −60° C. After the resultant white suspension had been stirred for2 hours, 2.2 equivalents of chlorophosphine in 25 ml of toluene wereadded. The reaction mixture was slowly heated to ambient temperature andwas stirred overnight. The solvent was removed under vacuum and theresidue was dissolved in a mixture of toluene and saturated sodiumchloride solution in a ratio of 2:1. The organic phase was removed andthe aqueous phase was extracted three times with toluene. After thecombined organic extracts had been dried under vacuum and the resultantresidue had been washed with hexane, a white powder was isolated. Theligands were obtained in pure form after recrystallization; 2 a fromethanol (yield 64%), 2 b from DCM (yield 52%) and 2 c from toluene(yield 75%).

[0048] The physical parameters of the resultant compounds are reproducedbelow:

[0049] Properties of 2 a:

[0050] mp.: 194 -195° C.

[0051]¹H—NMR(in CDCl₃):

[0052] δ[ppm] 7.38 (d, ⁴J(H,H)=2.2 Hz, 2H; H^(1.8)), 7.24 (m, 20H;phenyl), 6.53 (bd, ⁴J(H,H)=2.1 Hz, 2H; H^(3.6)), 1.68 (s, 6H; CH₃), 1.11(s, 18H; t=butyl).

[0053]¹³C{¹H}—NMR (in CDCl):

[0054] δ[ppm] =150.7 (t, J(P,C)=19.1 Hz; CO), through-space P—Pcoupling=25.2 Hz, 145.4 (C^(2.7)), 137.0 (t, J(P,C)=13.1 Hz; PC), 134.2(t, J(P,C)=20.4 Hz; PCCH); 129.7 (C3.6), 129.1 (CC⁹), 128.3 (d,J(P,C)=6.0 Hz; PCCHCH), 128.3 (PCCHCHCH), 124.9 (t, J(P,C)=18.9 Hz;C^(4.5)), 123.2 (C^(1.8)), 35.1 (C⁹), 34.7 (C(CH₃)₃, 32.4 (C⁹ CH₃), 31.5(C(CH₃)₃).

[0055]³¹P{¹H}—NMR (in CDCl₃):

[0056] δ[ppm]=-16.2

[0057] Elemental Analysis: Calculated: C 81.78% H 6.69% Found:    81.71%    7.01%

[0058] Properties of 2 b:

[0059] mp.: 330°

[0060]¹H—NMR (in CDCl₃):

[0061] δ[ppm]=8.35 (dd, ³J(H,H)=7.5 Hz, ⁴J(H,H)=1.6 Hz, 4H; DBP—H¹),7.97 (d, ³J(H,H)=7.5 Hz, 4H; DBP—H⁴), 7.49 (dt, ³J(H,H) =7.5 Hz,⁴J(H,H)=1.4 Hz, 4H; DBP—H²), 7.41 (dt, ³J(H,H) =7.4 Hz ⁴J(H,H)=1.3 Hz,4H; DBP—H³), 7.38 (d, ⁴J(H,H) =2.4 Hz, 2H; H^(1.8)), 6.76 (dt,⁴J(H,H)=2.3 Hz, J(P,H)=2.5 Hz, 2H; H^(3.6)), through-space P—Pcoupling=37.8 Hz, 1.69 (s, 6H; CH₃), 1.12 (s, 18H; t-butyl).

[0062]¹³C{¹H—NMR (in CDCl₃:

[0063] δ[ppm]=151.0 (t, J(P,C)=19.6 Hz; CO), 146 (C^(2.7)), 144.1 (PCC),142.5 (t, J(P,C)=4.5 Hz; P,C), 131.9 (t, J(P.C)=26.4 Hz; DBP—C⁴); 129.5(CC⁹), 128.7 (DBP—C²), 127.5 (t, J(P,C) =3.0 Hz; DBP—C³), 126.5(C^(3.6)), 124.5 (C^(1.8)), 124.5 (m, J(P,C)=25.7 Hz; C^(4.5)), 121.6(DBP—C¹), 35.1 (C⁹), 34.9 (C(CH₃)₃), 33.2 (C⁹ CH₃), 31.6 (C(CH₃)₃).

[0064]³¹P{¹H}—NMR (in CDCl₃):

[0065] δ[ppm]=−20.8

[0066] Elemental Analysis: Calculated: C 81.54%, H 5.73% Found:   82.19%     6.46%

[0067] Properties of 2 c:

[0068] mp.: 336 -338° C.

[0069]¹H—NMR (in CDCl₃:

[0070] δ[ppm]=b 8.18 (t, ³J(H,H)=7.2 Hz, ³J(P,H)=14.4 Hz, 4H; PP—H¹),through-space P—P coupling=65 Hz, 7.40 (dt, ³J(H,H)=7.7 Hz, ⁴J(H,H)=1.3Hz, 4H; PP—H³, 7.26 (s, 2H; H^(1.8)), 7.24 (d, ³J(H,H)=8.2 Hz, 4H;PP—H⁴), 7.17 (t, ³J(H,H)=7.3 Hz, 4H; PP—H²), 6.67 (s, 2H; H^(3.6)), 1.55(s, 6H; CH₃), 1.10 (s, 18H; t-butyl).

[0071]¹³C{¹H}—NMR (CDCl₃):

[0072] δ[ppm]=155.8 (PP—CO), 149.6 (t, J(P ,C)=21.3 Hz; CO), 145.1(C^(2.7)), 135.5 (t, J(P,C)=43.1 Hz; PP—C¹), 130.5 (PP—C³), 128.8 (CC⁹), 128.5 (C^(3.6)), 125.7 (t, J(P,C)=29.0 Hz;

[0073] PP—PC), 123.8 (C^(1.8)), 123.3 (t, J(P,C)=11.1 Hz; PP—C²), 118.3(C^(4.5)), 117.4 (PP—C⁴), 34.4 (C⁹), 34.1 (C(CH₃)₃), 32.7 (C⁹ CH₃), 30.9(C(CH₃)₃—

[0074]³¹P {¹H}—NMR (CDCl₃):

[0075] δ[ppm]=−69.9

[0076] Elemental Analysis: Calculated: C 78.47%, H 5.6% Found:    78.53%    6.17%

[0077] The diphosphine ligands 2 a, 2 b and 2 c described above wereused in the hydroformylation of internal olefins in accordance with theconditions described below:

[0078] The reactions were carried out in a 180 ml stainless steelautoclave in toluene at 80° C. under a CO/H₂ atmosphere (ratio 1:1) atan initial pressure of 20 bar. The catalyst precursor was Rh(CO₂)(dipivaloyl methanoate), the rhodium concentration was 1.0 mmol, and theratio of Rh:P:1-octene was 1:10:673. The conversion, the 1/b ratio andthe selectivities for the isomerized olefins and the linear aldehydewere determined by gas chromatography, using decane as internalstandard.

[0079] TOF here denotes the turnover frequency which is calculated as(moles of aldehyde) (moles of catalyst)⁻¹(h)⁻¹. TABLE 1 Results ofhydroformylation of 1-octene: Selectivity Conver- Selectivity (lin. tsion (isomers aldehyde Ligand (min) (%) in %) l/b in %) TOF PPh₃ 5.3 261.2 3.1 74 1880 2a 30 21 3.9 49 94  250 2b 24 28 16 65 83  360 2c 8.5 2713 68 86 1100

[0080] TABLE 2 Results of hydroformylation of trans 2- and 4-octene:Selectivity (lin. t Conversion aldehyde Ligand Substrate (h) (%) l/b in%) TOF 2b 2-octene 1.0 10 9.5 90 65 2c 2-octene 1.0 22 9.2 90 112 2b4-octene 17 54 6.1 86 15 2c 4-octene 17 67 4.4 81 20

[0081] The reaction conditions were identical to those of Table 1,except that the temperature was 120° C. and the pressure was 2 bar.TABLE 3 Results of hydroformylation of n-octene mixture: Selectivity tConversion (lin. aldehyde) Ligand (h) (%) l/b in %) TOF PPh₃ 2.8 57 0.533 318 2c 2.8 63 1.8 64 393  2c* 2.0 66 1.4 58 517 2c 1.7 68 1.7 63 648

[0082] The reaction conditions were identical to those of Table 2 exceptthat the pressure was 10 bar. TABLE 4 Results of hydroformylation ofn-butene mixture: Selectivity t Conversion (lin. aldehyde) Ligand (h)(%) l/b in %) TOF 2c 1,5 82 6,7 87  985  2c* 1,5 84 4,6 82 1050

[0083] The reaction conditions were identical to those of Table 2 exceptthat the pressure was 10 bar.

[0084] Various modifications of the products and process of theinvention may be made without departing from the spirit or scope thereofand it is to be understood that the invention is to be limited only asdefined in the appended claims.

What we claim is:
 1. A bidentate phosphine ligand of the formula

wherein R1, R2, R3 and R4 are independently selected from the group consisting of hydrogen, fluorine, alkyl of 1 to 8 carbon atoms, alkoxy of 1 to 8 carbon atoms, acyloxy of an organic carboxylic acid of 1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, aryloxy of 6 to 18 carbon atoms, —CN, —CF₃, —CHO, —SO₃H, —SO₃M, —SO2R, —SOR, —NH₂, —NH—alkyl of 1 to 8 carbon atoms, —N—alkyl₂ of 1 to 8 carbon atoms, —NHCO-alkyl, —N—(alkyl)—(CO—(alkyl) where the alkyl have 1 to 4 carbon atoms, —COO—alkyl of 1 to 8 carbon atoms, —CONH₂, —CO—alkyl of 1 to 8 carbon atoms, —NHCOH, —NHCOO—alkyl of 1 to 4 carbon atoms, —CO—aryl of 1 to 8 carbon atoms, —COO—aryl of 1 to 8 carbon atoms, —CHCH—CO₂—alkyl of 1 to 8 carbon atoms, —PO—(-aryl)₂ of 1 to 8 carbon atoms, —PO—(alkyl₂) of 1 to 4 carbon atoms; M is a cation selected from the group consisting of alkali metal ions, alkaline earth metal ions, —NR₂H₂, —NR₃H, —NRH₃, —NR₄, —NH₄, —PR₂H₂, —PR₃H, —PRH₃, —PR4 and —PH₄; or R1, R2, R3 and R4, with one another, together form at least one aliphatic or aromatic ring of 5 to 20 carbon atoms; E is a bridge linking the two phosphorus atoms, where the number of atoms situated between the two phosphorus atoms is 2 and 6, selected from the group consisting of C, N, Si, S, O, P, Fe and As; X is selected from the group consisting of —O—, —S—, —Si (R^(a))₂—, —Si (OR^(a))₂—, —N(C(O)R^(a))—, —N(Rb)—, —C(R^(c)) (R^(c))—, —C (O)—, —N(SiR^(d))—, —P(R^(d))—, —P(O) (R^(d))—, —C=C(R^(c)) (R^(c))— and —P(OR^(d))— wherein R^(a) is alkyl of 1 to 8 carbon atoms, R^(b) is aryl of 6 to 18 carbon atoms, R^(c) is selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, alkoxy of 1 to 8 carbon atoms, aryloxy of 6 to 18 carbon atoms, R^(a)(O)— and R^(b)(O); and R^(d) is one of R^(a) or R^(b).
 2. The ligand of claim 1 wherein E is selected from the group consisting of

wherein X is selected from the group consisting of —O—, —S—, —Si(R^(a))₂—, —Si(OR^(a))₂—, —N(C(O)R^(a))—, —N(R^(b))—, —C(R^(c)) (R^(c))—, —C(O)—, —N(SiR^(d))—, —P(R^(d))—, —P(O) (R^(d))—, —C=C(R^(c)) (R^(c))— and —P(OR^(d))—, R^(a) is alkyl of 1 to 8 carbon atoms R^(b) is aryl of 6 to 18 carbon atoms R^(c) is selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, alkoxy of 1 to 8 carbon atoms, aryloxy of 6 to 18 carbon atoms, R^(a)(O)— or R^(b)(O)—; and R^(d) is one of R^(a) or R^(b); Y is oxygen or sulfur; and R5s are individually aryl of 6 to 18 carbon atoms or alkyl of 1 to 8 carbon atoms.
 3. The ligand of claim 1 wherein E is selected from the group consisting of

wherein R⁶ is alkyl of 1 to 6 carbon atoms or aryl of 6 to 18 carbon atoms, Z is oxygen or nitrogen and n is an integer from 2 to
 6. 4. A process for the preparation of a linear aldehyde comprising hydroformylating an internal olefin of 4 to 12 carbon atoms with carbon monoxide and hydrogen in the presence of a bidentate phosphine ligand of claim
 1. 5. The process of claim 4 wherein E is selected from the group consisting of

wherein X is selected from the group consisting of —O—, —S—, —Si(R^(a))₂—, —Si(OR^(a))₂—, —N(C (O)R^(a))—, —N(R^(b))—, —C(R^(c))R^(c))—, —C(O)—, —N(SiR^(d))—, —P(R^(d))—, —P(O) (R^(d))—, —C=(R^(c)) (R^(c))— and —P(OR^(d))—, R^(a) is alkyl of 1 to 8 carbon atoms R^(b) is aryl of 6 to 18 carbon atoms R^(c) is selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, alkoxy of 1 to 8 carbon atoms, aryloxy of 6 to 18 carbon atoms, R^(a)(O)— or R^(b)(O)—; and R^(d) is one of R^(a) or R^(b); Y is oxygen or sulfur; and R5s are individually aryl of 6 to 18 carbon atoms or alkyl of 1 to 8 carbon atoms.
 6. The process of claim 4 wherein E is selected from the group consisting of

wherein R⁶ is alkyl of 1 to 6 carbon atoms or aryl of 6 to 18 carbon atoms, Z is oxygen or nitrogen and n is an integer from 2 to
 6. 7. The process of claim 4 wherein the reaction is carried out in the presence of 1 to 1000 ppm of rhodium based on the total reaction mixture.
 8. The process of claim 7 wherein rhodium is present at 10 to 250 ppm.
 9. The process of claim 7 wherein the ratio of rhodium to ligand is 1:1 to 1:100.
 10. The process of claim 7 wherein the ratio of rhodium to ligand is 1:1 to 1:20.
 11. The process of claim 4 wherein the hydroformylation is effected at 10 to 180° C.
 12. The process of claim 4 wherein the hydroformylation is effected at 80 to 140° C.
 13. The process of claim 4 wherein the reaction is effected at a pressure of 0.1 to 200 bar.
 14. The process of claim 4 wherein the hydroformylation is effected in the presence of a solvent selected from the group consisting of ether, carbon dioxide, fluorinated hydrocarbons, toluene and benzene.
 15. The process of claim 4 wherein the hydroformylation is effected in a polar aprotic solvent selected from the group consisting of dimethylformamide, dimethylacetamide and N-methylpyrrolidone.
 16. The process of claim 4 wherein the hydroformylation is effected in the presence of an oligomeric aldehyde.
 17. The process of claim 16 wherein the oligomeric aldehyde is the trimer of the aldehyde to be formed.
 18. The process of claim 11 wherein the hydroformylation is effected in a two phase with water.
 19. The process of claim 4 wherein the ratio of carbon monoxide to hydrogen is 1:10 to 10:1.
 20. The process of claim 4 wherein the ratio of carbon monoxide to hydrogen is 1:2 to 2:1. 